She was explaining that one of her all-time favorite ads was a radio spot that featured a dog barking at politicians who said things that were false.

Clinton said: “I want to figure out how we can do that with Republicans. We need to get that dog and follow them around and every time they say these things like, 'Oh, the Great Recession was caused by too much regulation,' arf, arf, arf, arf."

Trump's response: "If I did something like that I would be ridiculed."

There was also a war of words on the campaign trail between Donald Trump and the Bush brothers.

Jeb, George W. and former first lady Laura Bush campaigned together for the first time in South Carolina on Monday. The former president also took a thinly veiled swipe at Trump.

George W. Bush said: “Americans are angry and frustrated, but we don’t need someone in the Oval Office who mirrors and inflames our frustration.”